Atoms — Physics STD 12 Science — Question

The temperature bellow which a material becomes a superconductor is called:

The x-component of the resultant of several vectors:

1. Is equal to the sum of the x-components of the vectors.
2. May be smaller than the sum of the magnitudes of the vectors.
3. May be greater than the sum of the magnitudes of the vectors.
4. May be equal to the sum of the magnitudes of the vectors.

A magnifying glass is to be used at the fixed object distance of 1 inch. If it is to produce an erect image magnified 5 times its focal length should be

(a) 0.2 inch

(b) 0.8 inch

(c) 1.25 inch

(d) 5 inch

A logic gate is an electronic circuit which

(a) Makes logic decisions

(b) Allows electrons flow only in one direction

(c) Works binary algebra

(d) Alternates between 0 and 1 values

Consider the following two statements A and B and identify the correct choice given in the answers

(A) Duddells thermo-galvanometer is suitable to measure direct current only

(B) Thermopile can measure temperature differences of the order of

(a) Both A and B are true	(b) Both A and B are false
(c) A is true but B is false	(d) A is false but B is true

The ratio of the forces between two small spheres with constant charge (a) in air (b) in a medium of dielectric constant K is

(a) 1 : K

(b) K : 1

(c)

(d)

Weber/m²  is equal to

(a) Volt

(b) Henry

(c) Tesla

(d) All of these

Current i is carried in a wire of length L. If the wire is turned into a circular coil, the maximum magnitude of torque in a given magnetic field B will be

(a)

(a)

(c)

(d)

The oscillating electric and magnetic vectors of an electromagnetic wave are oriented along: